Commitments And Contingencies	3 Months Ended
Mar. 31, 2012
Commitments And Contingencies [Abstract]
Commitments And Contingencies	12. Commitments and Contingencies *Legal Proceedings* Durand Litigation On March 12, 2007, a putative class action suit captioned Jennifer A. Durand v. The Hanover Insurance Group, Inc., The Allmerica Financial Cash Balance Pension Plan was filed in the United States District Court for the Western District of Kentucky. The named plaintiff, a former employee who received a lump sum distribution from the Company's Cash Balance Plan (the "Plan") at or about the time of her termination, claims that she and others similarly situated did not receive the appropriate lump sum distribution because in computing the lump sum, the Company understated the accrued benefit in the calculation. The Plaintiff filed an Amended Complaint adding two new named plaintiffs and additional claims on December 11, 2009. In response, the Company filed a Motion to Dismiss on January 30, 2010. In addition to the pending claim challenging the calculation of lump sum distributions, the Amended Complaint includes: (a) a claim that the Plan failed to calculate participants' account balances and lump sum payments properly because interest credits were based solely upon the performance of each participant's selection from among various hypothetical investment options (as the Plan provided) rather than crediting the greater of that performance or the 30 year Treasury rate; (b) a claim that the 2004 Plan amendment, which changed interest crediting for all participants from the performance of participant's investment selections to the 30 year Treasury rate, reduced benefits in violation of the Employee Retirement Income Security Act of 1974 ("ERISA") for participants who had account balances as of the amendment date by not continuing to provide them performance-based interest crediting on those balances; and (c) claims for breach of fiduciary duty and ERISA notice requirements arising from the various interest crediting and lump sum distribution matters of which Plaintiffs complain. The District Court granted the Company's Motion to Dismiss the additional claims on statute of limitations grounds by a Memorandum Opinion dated March 31, 2011, leaving the claims substantially as set forth in the original March 12, 2007 complaint. Plaintiffs filed a Motion for Reconsideration of the District Court's decision to dismiss the additional claims, which was denied with respect to the claims set forth in (a) and (b) above; however, the Court did allow the fiduciary duty claims to stand. At this time, the Company is unable to provide a reasonable estimate of the potential range of ultimate liability if the outcome of the suit is unfavorable. This matter is still in the early stages of litigation. The extent to which any of the Plaintiffs' multiple theories of liability, some of which are overlapping and others of which are quite complex and novel, are accepted and upheld on appeal will significantly affect the Plan's or the Company's potential liability. It is not clear whether a class will be certified or, if certified, how many former or current Plan participants, if any, will be included. The statute of limitations applicable to the alleged class has not yet been finally determined and the extent of potential liability, if any, will depend on this final determination. In addition, assuming for these purposes that the Plaintiffs prevail with respect to claims that benefits accrued or payable under the Plan were understated, then there are numerous possible theories and other variables upon which any revised calculation of benefits as requested under Plaintiffs' claims could be based. It is likely that any adverse judgment in this case would be against the Plan. Such a judgment would be expected to create a liability for the Plan, with resulting effects on the Plan's assets available to pay benefits. The Company's future required funding of the Plan could also be impacted by such a liability. Hurricane Katrina Litigation In August 2007, the State of Louisiana filed a putative class action in the Civil District Court for the Parish of Orleans, State of Louisiana, entitled State of Louisiana, individually and on behalf of State of Louisiana, Division of Administration, Office of Community Development ex rel The Honorable Charles C. Foti, Jr., The Attorney General For the State of Louisiana, individually and as a class action on behalf of all recipients of funds as well as all eligible and/or future recipients of funds through The Road Home Program v. AAA Insurance, et al., No. 07-8970. The complaint named as defendants over 200 foreign and domestic insurance carriers, including the Company, and asserts a right to benefit payments from insurers on behalf of current and former Louisiana citizens who have applied for and received or will receive funds through Louisiana's "Road Home" program. The case was thereafter removed to the Federal District Court for the Eastern District of Louisiana. On March 5, 2009, the court issued an Order granting in part and denying in part a Motion to Dismiss filed by Defendants. The court dismissed all claims for bad faith and breach of fiduciary duty and all claims for flood damages under policies with flood exclusions or asserted under Louisiana's Valued Policy Law, but rejected the insurers' arguments that the purported assignments from individual claimants to the state were barred by anti-assignment provisions in the insurers' policies. On April 30, 2009, Defendants filed a Petition for Permission to Appeal to the United States Court of Appeals for the Fifth Circuit (the "Fifth Circuit"), which was granted. On July 28, 2010, the Fifth Circuit certified the anti-assignment issue to the Louisiana Supreme Court. On May 10, 2011, the Supreme Court of Louisiana issued a decision holding that the anti-assignment provisions were not violative of public policy. The court also indicated, however, that such provisions would only serve to bar post-loss assignments if they clearly and unambiguously expressed that they apply to post-loss assignments. On June 28, 2011, the Fifth Circuit remanded the case to the Federal District Court for further proceedings consistent with the Louisiana's Supreme Court's opinion. On September 12, 2011, the State of Louisiana filed a Motion to Remand the case to state court, which was denied by an Order dated October 28, 2011. At this time, the Company is unable to provide a reasonable estimate of the potential range of ultimate liability. The Company is unable to determine how many policyholders have assigned claims under the Road Home program and, in any case, has no basis to estimate the amount of any differences between what the Company paid with respect to any such claim and the amount that the State of Louisiana may claim should properly have been paid under each policy. *Other Matters* The Company has been named a defendant in various other legal proceedings arising in the normal course of business. In addition, the Company is involved, from time to time, in examinations, investigations and proceedings by governmental and self-regulatory agencies. The potential outcome of any such action or regulatory proceedings in which the Company has been named a defendant or the subject of an inquiry or investigation, and its ultimate liability, if any, from such action or regulatory proceedings, is difficult to predict at this time. The ultimate resolutions of such proceedings are not expected to have a material effect on its financial position, although they could have a material effect on the results of operations for a particular quarter or annual period.

12. Commitments and Contingencies

Legal Proceedings

Durand Litigation

On March 12, 2007, a putative class action suit captioned Jennifer A. Durand v. The Hanover Insurance Group, Inc., The Allmerica Financial Cash Balance Pension Plan was filed in the United States District Court for the Western District of Kentucky. The named plaintiff, a former employee who received a lump sum distribution from the Company's Cash Balance Plan (the "Plan") at or about the time of her termination, claims that she and others similarly situated did not receive the appropriate lump sum distribution because in computing the lump sum, the Company understated the accrued benefit in the calculation.

The Plaintiff filed an Amended Complaint adding two new named plaintiffs and additional claims on December 11, 2009. In response, the Company filed a Motion to Dismiss on January 30, 2010. In addition to the pending claim challenging the calculation of lump sum distributions, the Amended Complaint includes: (a) a claim that the Plan failed to calculate participants' account balances and lump sum payments properly because interest credits were based solely upon the performance of each participant's selection from among various hypothetical investment options (as the Plan provided) rather than crediting the greater of that performance or the 30 year Treasury rate; (b) a claim that the 2004 Plan amendment, which changed interest crediting for all participants from the performance of participant's investment selections to the 30 year Treasury rate, reduced benefits in violation of the Employee Retirement Income Security Act of 1974 ("ERISA") for participants who had account balances as of the amendment date by not continuing to provide them performance-based interest crediting on those balances; and (c) claims for breach of fiduciary duty and ERISA notice requirements arising from the various interest crediting and lump sum distribution matters of which Plaintiffs complain. The District Court granted the Company's Motion to Dismiss the additional claims on statute of limitations grounds by a Memorandum Opinion dated March 31, 2011, leaving the claims substantially as set forth in the original March 12, 2007 complaint. Plaintiffs filed a Motion for Reconsideration of the District Court's decision to dismiss the additional claims, which was denied with respect to the claims set forth in (a) and (b) above; however, the Court did allow the fiduciary duty claims to stand.

At this time, the Company is unable to provide a reasonable estimate of the potential range of ultimate liability if the outcome of the suit is unfavorable. This matter is still in the early stages of litigation. The extent to which any of the Plaintiffs' multiple theories of liability, some of which are overlapping and others of which are quite complex and novel, are accepted and upheld on appeal will significantly affect the Plan's or the Company's potential liability. It is not clear whether a class will be certified or, if certified, how many former or current Plan participants, if any, will be included. The statute of limitations applicable to the alleged class has not yet been finally determined and the extent of potential liability, if any, will depend on this final determination. In addition, assuming for these purposes that the Plaintiffs prevail with respect to claims that benefits accrued or payable under the Plan were understated, then there are numerous possible theories and other variables upon which any revised calculation of benefits as requested under Plaintiffs' claims could be based. It is likely that any adverse judgment in this case would be against the Plan. Such a judgment would be expected to create a liability for the Plan, with resulting effects on the Plan's assets available to pay benefits. The Company's future required funding of the Plan could also be impacted by such a liability.

Hurricane Katrina Litigation

In August 2007, the State of Louisiana filed a putative class action in the Civil District Court for the Parish of Orleans, State of Louisiana, entitled State of Louisiana, individually and on behalf of State of Louisiana, Division of Administration, Office of Community Development ex rel The Honorable Charles C. Foti, Jr., The Attorney General For the State of Louisiana, individually and as a class action on behalf of all recipients of funds as well as all eligible and/or future recipients of funds through The Road Home Program v. AAA Insurance, et al., No. 07-8970. The complaint named as defendants over 200 foreign and domestic insurance carriers, including the Company, and asserts a right to benefit payments from insurers on behalf of current and former Louisiana citizens who have applied for and received or will receive funds through Louisiana's "Road Home" program. The case was thereafter removed to the Federal District Court for the Eastern District of Louisiana.

On March 5, 2009, the court issued an Order granting in part and denying in part a Motion to Dismiss filed by Defendants. The court dismissed all claims for bad faith and breach of fiduciary duty and all claims for flood damages under policies with flood exclusions or asserted under Louisiana's Valued Policy Law, but rejected the insurers' arguments that the purported assignments from individual claimants to the state were barred by anti-assignment provisions in the insurers' policies. On April 30, 2009, Defendants filed a Petition for Permission to Appeal to the United States Court of Appeals for the Fifth Circuit (the "Fifth Circuit"), which was granted. On July 28, 2010, the Fifth Circuit certified the anti-assignment issue to the Louisiana Supreme Court. On May 10, 2011, the Supreme Court of Louisiana issued a decision holding that the anti-assignment provisions were not violative of public policy. The court also indicated, however, that such provisions would only serve to bar post-loss assignments if they clearly and unambiguously expressed that they apply to post-loss assignments. On June 28, 2011, the Fifth Circuit remanded the case to the Federal District Court for further proceedings consistent with the Louisiana's Supreme Court's opinion. On September 12, 2011, the State of Louisiana filed a Motion to Remand the case to state court, which was denied by an Order dated October 28, 2011.

At this time, the Company is unable to provide a reasonable estimate of the potential range of ultimate liability. The Company is unable to determine how many policyholders have assigned claims under the Road Home program and, in any case, has no basis to estimate the amount of any differences between what the Company paid with respect to any such claim and the amount that the State of Louisiana may claim should properly have been paid under each policy.

Other Matters

The Company has been named a defendant in various other legal proceedings arising in the normal course of business. In addition, the Company is involved, from time to time, in examinations, investigations and proceedings by governmental and self-regulatory agencies. The potential outcome of any such action or regulatory proceedings in which the Company has been named a defendant or the subject of an inquiry or investigation, and its ultimate liability, if any, from such action or regulatory proceedings, is difficult to predict at this time. The ultimate resolutions of such proceedings are not expected to have a material effect on its financial position, although they could have a material effect on the results of operations for a particular quarter or annual period.